Running bunco for 18
For 18 players you will need 4 tables, 12 dice (three a table), a bell for the head table, and 5 sheets of paper for the score cards (four to a page). With 16 or 20 players nobody would sit out.
This is a mixer chart: instead of winners moving to the head table, everyone follows the chart so you play with as many different people as possible. Partners sit across. Roll for 21 as usual; when the head table calls the round, mark a win or loss and any buncos on your card and find your next seat.
Some bunco groups fill empty seats with a "ghost" instead, and the ghost's partner rolls for both. This chart rests 2 players each round instead, so every score on the night is a real one.
Each score card lists that player's table, partner and opponents for every round. Want names on them, a different number of rounds or a fresh shuffle? Open this chart in the planner.